High wind, sleet and icy conditions moved into the Kansas City metropolitan area Saturday night, the first wave of a winter storm that was expected to dump heavy snow across the region.

The heaviest snow was expected to fall late Saturday and in the first half of the day on Sunday. The snow should move out of the region by Sunday evening. KMBC 9 chief meteorologist Bryan Busby said he expected 5 to 8 inches of snow in the Kansas City metropolitan area.

Driving conditions deteriorated throughout the late afternoon and early evening as the snow began to fall. Numerous crashes were reported on area highways.

Kansas City Police Chief Darryl Forte urged people to drive with caution. He said streets and highways were slicker than they appear.

Kansas City said it would begin plowing primary and secondary streets at 7:30 p.m. Saturday. It said residential streets won't be touched until Sunday at the earliest. Kansas City officials are asking residents to not park on the street during snow. Residents who don't have an option are asked to park on the north or west sides of streets so plows can get through.

Other communities in the Kansas City area, including Overland Park and Lee's Summit, also had snow-removal schedules in place.

The ATA bus system advised drivers that it planned to provide Metro service throughout the day on Sunday, but it warned that there could be delays.

Gov. Jay Nixon activated the State Emergency Operations System, coordinating communications between agencies throughout the state. He urged drivers to avoid any unnecessary travel until the storm was over.

Nixon has postponed a planned trip to Canada because of the weather.

Whiteman Air Force Base in central Missouri cut short weekend drills for more than 1,000 reservists because of the pending storm.